(1)15x-33=42
15x-33+33=42+33
15x=75
x=5
验算:把x=5代入方程的左边,
左边=15×5-33=75-33=42
左边=右边
所以x=5是原方程的解.
(2)5x+2.6×5=25
5x+13=25
5x+13-13=25-13
5x=12
x=2.4
(3)13x-5x=32.8
8x=32.8
8x÷8=32.8÷8
x=4.1
(4)4x-
=8 9
1 9
4x-
+8 9
=8 9
+1 9
8 9
4x=1
x=
1 4